package com.rpframework.utils;

public class DistanceUtils {
	public static final double EARTH_RADIUS = 6378137;

	public static double rad(double d) {
		return d * Math.PI / 180.0;
	}

	/**
	 * 根据两点间经纬度坐标（double值），计算两点间距离，单位为米
	 * 
	 * @param lng1
	 * @param lat1
	 * @param lng2
	 * @param lat2
	 * @return
	 */
	public static double getDistance(double lng1, double lat1, double lng2,
			double lat2) {
		double radLat1 = rad(lat1);
		double radLat2 = rad(lat2);
		double a = radLat1 - radLat2;
		double b = rad(lng1) - rad(lng2);
		double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2)
				+ Math.cos(radLat1) * Math.cos(radLat2)
				* Math.pow(Math.sin(b / 2), 2)));
		s = s * EARTH_RADIUS;
		s = Math.round(s * 10000) / 10000;
		return s;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		double distance = getDistance(120.1192620000, 30.3232020000, 115.9255760000, 28.6683660000);
		System.out.println("Distance is:" + distance);
		
		System.out.println(getDistance(100.182767, 200, 120.1091498352682, 30.33513759001055));
	}
}